Metamorphic Or Sedimentary (With Staining)

Gossan (Iron Hat)

Limonitic Gossan (Fe-oxide/hydroxide complex)

Chalcedony Pebble / Rough Agate

Silicon Dioxide (SiO2)

Quartz (Iron-Stained)

Silicon Dioxide (SiO2)

Quartzite with Iron Inclusions

Metamorphosed Quartz (SiO2)

Quartz-bearing reddish metamorphic rock, possibly ferruginous quartzite or jasper vein

Quartz (SiO₂) with iron oxides; likely quartzite or iron-rich jasper

Aura Quartz Bead

Silicon dioxide (SiO2) with metal coating

Milky Quartz with Iron Inclusions

Silicon Dioxide (SiO2)

Likely garnet-bearing schist or gneiss

Mica schist/gneiss containing quartz, feldspar, mica, and possible almandine garnet

Iron-stained quartz-bearing rock, possibly weathered granite or gneiss

Quartz–feldspar rock with iron-oxide staining; exact identification requires testing

Sandstone (Ferruginous)

Arenite with iron oxide cement (Fe2O3)

Conglomerate

Conglomerate Sedimentary Rock

Ferruginous Quartz

Silicon Dioxide (SiO2) with Iron Oxide (Limonite/Hematite)

Tumbled gray quartz-rich stone, possibly quartzite or chert

Likely quartzite (microcrystalline SiO₂), though the photograph cannot distinguish it confidently from gray chert or silicified limestone

Rounded gray-brown river pebble

Indeterminate lithic clast; likely weathered sandstone or fine-grained metamorphic rock

Quartz Pebble

Silicon Dioxide (SiO2)

Asphalt aggregate

Human-made bituminous asphalt containing crushed silicate rock aggregate

Tumbled orange jasper/quartzite pebble

Jasper, microcrystalline quartz (SiO₂), likely iron-oxide colored

Weathered Quartzite or Chert Pebble

Silicon Dioxide (SiO2)

Iron-stained quartz-rich rock (possibly ironstone or quartzite)

Quartz-rich silicate rock with iron oxides; exact rock type cannot be confirmed from the image

Iron-stained Quartzite

Metamorphic Quartz (SiO2) with limonite/hematite staining

Quartz with Iron Staining

Silicon Dioxide (SiO2)

Red Sandstone

Arenite (Ferruginous Sandstone)

Iron-rich quartzite or ferruginous metamorphic rock

Ferruginous quartzite, likely hematite/goethite-bearing quartzite; SiO₂ with Fe₂O₃/FeO(OH)

Polished brown gemstone, likely jasper or bronzite

Jasper: microcrystalline SiO₂; possible bronzite: (Mg,Fe)SiO₃

Milky quartz with iron-oxide staining

Quartz, silicon dioxide (SiO₂), with limonite/goethite staining

Smooth river pebble, likely quartz-rich sandstone or quartzite

Indeterminate quartz-rich clast; possibly quartzite (mostly SiO₂)

Milky Quartz with Algae/Chlorite

Silicon Dioxide (SiO2)

Pyrite (on Quartz/Host Rock)

Iron Sulfide (FeS₂)

Iron-stained quartz crystal cluster

Quartz (SiO₂), likely iron-oxide-stained; exact variety uncertain

Sandstone

Arenite (Siliclastic sedimentary rock)

Mixed rock collection

Labeled specimens appear to include iron-rich rock, schist, basalt, serpentinite, and shale

Tumbled quartz-bearing rock, possibly garnet-bearing quartzite

Quartz-dominant silicate rock; visible minerals may include quartz, iron oxides, and dark mica or amphibole

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Quartzite

Metamorphic Quartzite (SiO2)

Quartzite with inclusions

Quartzite

Weathered brown rock fragment, possibly iron-rich sandstone or altered basalt

Indeterminate; likely an iron-oxide–stained silicate rock

Milky Quartz

Silicon Dioxide (SiO2)

Chrysocolla on Matrix

Hydrated copper silicates ((Cu,Al)2H2Si2O5(OH)4·nH2O)

Weathered quartz-rich rock, likely sandstone or quartzite

Quartz-dominated lithic fragment; probable quartz sandstone (SiO₂)

Likely weathered limestone or calcitic marble

Calcite (CaCO₃), probably micritic limestone; marble is a possible metamorphic alternative

Sandstone (Banded)

Clastic Sedimentary Rock (primarily SiO2 with Iron Oxide staining)